Modal Loss Factors of Thick Three-Layer Cylinders With Viscoelastic Core

Abstract

Abstract An analytical solution to the free vibration of a damped three-layer thick sandwiched cylinder of infinite extend is presented. The constrained layer damping is accomplished by sandwiching a linear viscoelastic material between two isotropic elastic cylinders with the same properties. The governing equation is derived based on elasto-dynamic theory utilizing complex elastic moduli. Dimensionless natural frequencies and modal loss-factors are extracted. Special case for a three-layer sandwiched cylinder with similar elastic properties is considered. The computed dimensionless frequencies are compared with previously established results. The comparison indicates the validity of the proposed mathematical procedures. In addition, the effects of various values of material damping for the core layer and ratio of the core shear modulus to the shear modulus of the elastic cylinders on natural frequencies and modal loss-factors are studied. For a given configuration, modal information for the first two modes for n = 0, 1, 2, 3 and 4 are presented for a wide range of core material damping and G2/G1 ratio.